The present invention relates to a remote control unit, for example of the type used together with a motor vehicle key to remotely control the opening or the closing of the vehicle doors.
At present, it is common practice for motor vehicle keys to be combined with remote control devices, housed in the bow end of the key or in an associated key holder. These devices are subject to environmental attacks, such as, for example, falling into a pool of water, and must therefore be especially protected, both for watertightness and for impact resistance. Such a key is known from the prior art, for example, from document EP-A-0 690 189, the bow end of which key forms a unit in two parts, one of these parts comprising a deformable member acting as a control button for the remote control, this member being secured by a seal providing the peripheral watertightness of the unit. However, the remote control device comprises components such as light-emitting diodes or indicator lights which the seal of the prior art is limited to surrounding, thus achieving only purely relative watertightness. Such a unit is further known from document DE 94 00 748, in which the seal is produced in the form of a flexible membrane covering the internal wall of a half-unit and having a window transparent to emitted waves, while maintaining watertightness. Nevertheless, in the case of shock, the components of the device are likely to shift, thus compromising not only the watertightness, but also the proper operation of the device. In addition, this type of unit, combined with a key, is by nature often handled and subject to static electricity discharges likely to damage the enclosed electronic components.
The objective of the present invention is therefore to propose a remote control unit which takes into account the various types of environmental attack and allows the remote-control electronic device that it contains to be effectively and economically protected.
This objective of the invention together with others which will appear in the rest of the present description are achieved by means of the remote control unit, of the type formed by two half-shells enclosing a printed circuit and a seal designed to isolate said circuit from the external surroundings.
According to the invention, the seal is formed by a flexible membrane separating the unit into two chambers and comprising, at least locally, an electrically conducting zone.
According to an advantageous characteristic of the invention, one of the half-shells of the unit is designed to house a power-supply battery for the electronic circuit and the flexible membrane comprises at least one conducting zone, forming a protuberance connecting the electronic circuit to at least one of the battery terminals and simultaneously forming a retaining spring for the power-supply conductor and battery.
According to another characteristic of the invention, the unit is designed to engage with a metal key bit in order to form a key for a motor vehicle and has a hole through which a keyring passes and the flexible membrane comprises at least one conducting zone forming, on the one hand, a protuberance bearing against part of the key bit and extending, on the other hand, around the hole in the form of a flange projecting into the hole, constituting an escape path for static electricity discharges from the ring to the key bit.